<html>
<head>
<style>
#myStyle:-moz-display-comboboxcontrol-frame {
  -moz-user-input: none !important;
}
#myStyle:-moz-dropdown-list {
  -moz-user-input: none !important;
}
</style>
</head>
<body onload="getElementById('mySelect').setAttribute('id', 'myStyle');"><select id="mySelect"></select></body></html>
